There is a large body of evidence to support the effectiveness of CBT for depression, e.g. March compared the effects of CBT, medication and a mix of the two in 327 depressed teens. After 36 weeks 81% of the CBT group, 81% of the medication group, and 86% of the double group were significantly improved. The study showed CBT as effective as drugs. This suggests there is a good cause for making the therapy the first choice of treatment in healthcare systems like the NHS.